S.B.
You have my sympathies. I had two children 16 months apart, my youngest didn't sleep through the night until she was 15 months old. Because my husband worked the late shift he would handle the night time stuff, but it was still exhausting being woken up.
The night I weaned her off her bottle - put her to bed with cuddles not milk, she slept straight through and from then every night after. I will never know if she was suffering from reflux or waking herself up wetting her diaper but it was like a magic switch was flipped. Perhaps your son is suffering from the same unknown problem.